1. Field of the Invention
The invention relates to a method for carrying out monitoring in packet-oriented telecommunication and data networks.
2. Description of Related Art
The fundamental procedure for carrying out subscriber monitoring in telecommunication networks is described in ETSI GSM 03.33 (Tdoc SMG10 98 D047). In the Federal Republic of Germany, telecommunication services are monitored in line with the applicable legal provisions.
Packet-oriented telecommunication networks are cellular mobile radio networks based on the GSM standard using GPRS transmission methods (ETSI 03.60), for example. In contrast to line-conducted services, in this case the individual data packets are transmitted individually in the network using the TCP/IP protocol (in line with Internet Engineering Task Force IETF standard RFC 793/RFC 791), which means that the usual association between data transmission channel and communication subscriber does not exist.
The same method is applied on the public Internet. The same problems arise there.
When carrying out legal monitoring, particular problems are encountered with this type of transmission. The transmission channels are used by a large number of different customers with relatively short data packets in each case.
When monitoring is carried out, all data packets therefore need to be compared with a list of the subscribers which are to be actively monitored in order to filter out (to copy) those packets which can be attributed to the subscribers to be monitored in the transmission or reception direction.
Accordingly, the technical complexity rises as the bandwidth increases (more packets per unit time) and as the number of monitoring instances rises (longer list needing to be verified for each packet).
The components involved in switching (switching nodes, routers, gateways etc.) are equipped with microprocessor systems and their switching power is impaired quite considerably by the technical monitoring tasks. This is reflected in the costs because, as the monitoring tasks increase, more and also more powerful components need to be installed than would be the case for the pure switching tasks.
Since the monitoring tasks are among the legal requirements, these services have to be provided by the network operators, who need to bear the financial costs themselves.
It would therefore be of great commercial advantage if the processor complexity which needs to be provided for the legal monitoring tasks (Lawful Interception) could be reduced.